Use of dispersion polymers as friction reducers in aqueous fracturing fluids

Abstract

A method of reducing friction resulting from turbulent flow in an aqueous fracturing fluid in an oil field fracturing process comprising adding to the aqueous fracturing fluid an effective friction-reducing amount of one or more dispersion polymers, wherein the dispersion polymer is composed of from about 5 to about 95 mole percent of one or more nonionic monomers and from about 95 to about 5 mole percent of one or more cationic or anionic monomers and has a molecular weight of at least 100,000.

We claim:  
     
       1. A method of reducing friction resulting from turbulent flow in an aqueous fracturing fluid in an oil field fracturing process comprising adding to the aqueous fracturing fluid an effective friction-reducing amount of one or more dispersion polymers, wherein the dispersion polymer is composed of from about 5 to about 95 mole percent of one or more nonionic monomers and from about 95 to about 5 mole percent of one or more cationic or anionic monomers and has a molecular weight of at least 100,000. 
     
     
       2. The method of  claim 1  wherein the dispersion polymer is composed of from about 95 to about 50 mole percent of one or more nonionic monomers and from about 5 to about 50 mole percent of one or more cationic monomers selected from the group consisting of dialkylaminoalkyl acrylates and methacrylates and their quaternary or acid salts. 
     
     
       3. The method of  claim 2  wherein the cationic monomers are selected from dimethylaminoethyl acrylate methyl chloride quaternary salt and dimethylaminoethyl acrylate benzyl chloride quaternary salt. 
     
     
       4. The method of  claim 3  wherein the dispersion polymer is acrylamide/dimethylaminoethyl acrylate methyl chloride quaternary salt/dimethylaminoethyl acrylate benzyl chloride quaternary salt terpolymer. 
     
     
       5. The method of  claim 3  wherein the dispersion polymer is acrylamide/dimethylaminoethyl acrylate methyl chloride quaternary salt copolymer. 
     
     
       6. The method of  claim 1  wherein the dispersion polymer is composed of from about 95 to about 50 mole percent of one or more nonionic monomers and from about 5 to about 50 mole percent of one or more anionic monomers selected from the group consisting of acrylic acid, methacrylic acid and 2-acrylamido-2-methylpropanesulfonic acid and the salts thereof. 
     
     
       7. The method of  claim 6  wherein the dispersion polymer is acrylamide/acrylic acid sodium salt copolymer. 
     
     
       8. The method of  claim 6  wherein the dispersion polymer is acrylamide/acrylic acid. 
     
     
       9. The method of  claim 6  wherein the dispersion polymer is acrylamide/acrylic acid/acrylic acid sodium salt terpolymer. 
     
     
       10. The method of  claim 1  wherein the dispersion polymer has a molecular weight of at least 1,000,000. 
     
     
       11. The method of  claim 1  wherein the dispersion polymer has a molecular weight of at least 5,000,000. 
     
     
       12. The method of  claim 1  wherein the fracturing fluid is selected from the group consisting of fresh water, brines and aqueous acids. 
     
     
       13. The method of  claim 1  further comprising adding one or more corrosion inhibitors to the fracturing fluid. 
     
     
       14. The method of  claim 11  wherein the corrosion inhibitor is selected from the group consisting of quaternary ammonium salts, alky-substituted heterocycles, amides and imidazolines.